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 A278668 Expansion of Product_{n>=1} (1 - x^(5*n))/(1 - x^n)^3 in powers of x. 2
 1, 3, 9, 22, 51, 107, 218, 420, 788, 1428, 2531, 4375, 7430, 12377, 20313, 32833, 52402, 82585, 128750, 198588, 303428, 459375, 689710, 1027243, 1518709, 2229375, 3251022, 4710777, 6785378, 9717677, 13841991, 19614182, 27656250, 38810312, 54216128, 75406438 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..1000 FORMULA G.f.: Product_{n>=1} (1 - x^(5*n))/(1 - x^n)^3. a(n) ~ exp(2*Pi*sqrt(7*n/15)) * 7^(3/4) / (20 * 3^(3/4) * 5^(1/4) * n^(5/4)). - Vaclav Kotesovec, Nov 10 2017 EXAMPLE G.f.: 1 + 3*x + 9*x^2 + 22*x^3 + 51*x^4 + 107*x^5 + 218*x^6 + ... MATHEMATICA nmax = 30; CoefficientList[Series[Product[(1 - x^(5*k))/(1 - x^k)^3, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 10 2017 *) CROSSREFS Cf. Product_{n>=1} (1 - x^(5*n))/(1 - x^n)^k: A035959 (k=1), A160461 (k=2), this sequence (k=3), A278680 (k=4), A277212 (k=5), A182821 (k=6). Sequence in context: A143099 A160462 A000711 * A160526 A121589 A227454 Adjacent sequences:  A278665 A278666 A278667 * A278669 A278670 A278671 KEYWORD nonn AUTHOR Seiichi Manyama, Nov 25 2016 STATUS approved

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Last modified May 26 00:32 EDT 2020. Contains 334613 sequences. (Running on oeis4.)